BIOS recovery on NEC Versa One (M370)

I have a NEC Versa M370 model M4200
after a bad flash, the screen still black and it are no more booting
I tested the different methods I found but no one is working
I tested with USB key and CD with only one file "AMIBOOT.ROM" and I pressed many keys on startup (Ctrl+Home , Ctrl+PgUp , Ctrl+PgDn) but the laptop screen stay black.
When I start the laptop, I see the DVD drive reading but nothing happens after.
If a test with the usb key, it's blinking while 2 hours but no bip and the screen stay black